The class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon is now well known in the art. Such polymers are characterized by the repeating formula ##STR1## wherein A is a moiety derived from at least one ethylenically unsaturated hydrocarbon, The processes for the production of such polymers, now known as polyketones or polyketone polymers, is illustrated by van Broekoven et al, U.S. Pat. No. 4,843,144 and U.S. Pat. No. 4,880,903. The scope of the polymerization process is extensive, but generally employs a catalyst composition produced from a compound of palladium, cobalt or nickel, the anion of a strong nonhydrohalogenic acid and a bidentate ligand of phosphorus, nitrogen or sulfur. Good results are obtained through the use of catalyst compositions formed from, inter alia, bidentate ligands of phosphorus and such catalyst compositions are generally preferred.
In many polymerization processes for polyketone production the bidentate phosphorus ligand contains aromatic monovalent phosphorus substituents as in the above van Broeckhoven et al patents, and particularly preferred bidentate ligands for many polymerization processes are 1,3-bis(diphenylphosphino)propane and 1,3-bis[di(2-methoxyphenyl)phosphino]propane. For the production of certain linear alternating polymers, particularly when the ethylenically unsaturated hydrocarbon monomer is of relatively high molecular weight, e.g., the hydrocarbon monomer has at least 5 carbon atoms, the use of other bidentate phosphorus ligands results in more effective catalyst compositions. For example, in U.S. Pat. No. 5,066,778, the production of linear alternating copolymers of carbon monoxide and cyclopentane is disclosed. For this polymerization, tetraalkylbisphosphines are more suitable and preferred as the bidentate phosphorus ligand and particularly preferred is 1,3-bis(di-n-butylphosphino)propane. It would be of advantage, however, to provide for polyketone polymerization processes which employ more effective catalyst compositions formed in part from a different bis(dialkylphosphino)alkane.